function preloadImages() {
  var img1 = new Image(95,31);
  img1.src = "images/home_on.jpg";

  var img2 = new Image(80,31);
  img2.src = "images/contact_on.jpg";
 
  var img3 = new Image(95,31);
  img3.src = "images/clinicinfo_on.jpg";
  
  var img4 = new Image(128,31);
  img4.src = "images/eventschedule_on.jpg";

  var img5 = new Image(98,31);
  img5.src = "images/references_on.jpg";

  var img6 = new Image(59,31);
  img6.src = "images/links_on.jpg";

  var img7 = new Image(189,31);
  img7.src = "images/massagetherapy_on.jpg";
  
}

function doSwap(imgName, mSwitch) {
  document[imgName].src = "images/links/" + imgName + "_" + mSwitch + ".jpg";
}